1. Field of the Invention
This invention relates to improvements in ophthalmology and more particularly to improvements in artificial intraocular lenses (pseudophakoi) used for the correction of aphakia and re-establishment of binocularity in aphakia.
2. Discussion of the Prior Art
Well-fixed and well-centered intraocular lens implants are known to produce stable retinal images with stable space localization and offer the best chance of re-establishment of binocularity in cases of aphakia.
Many techniques of lens implantation, including suturing to the ciliary muscle as disclosed in U.S. Pat. No. 3,711,870 and iris diaphragm fixation as disclosed in U.S. Pat. No. 3,673,616 have been used. The latter is considered to be a safe procedure giving good stability and the present invention deals with improvements in this general type of pseudophakos. More particularly, the invention relates to improvements in "iridocapsular" and/or "iris clip" implants which have haptic sections respectively comprised of posterior and both posterior and anterior fastening elements all of which will be referred to hereinafter as iris clips. The iris clips may be in the form of loops and/or struts fastened to and extending away from the lenses.
Heretofore, iris clips have been formed of biologically inert metal wires which are at least in some respects, less than optimum in purpose. In this connection, even when formed of the least dense of useful metals or alloys, such loops and/or struts are relatively heavy in the eye, opaque and unaesthetic, less than optimally manipulatable before and/or during surgical implantation procedures and expensive both from the standpoint of precious metal cost and the intricacy of loop manufacture, not to mention the wire forming operation itself.
An already recognized alternative to the use of metals for iris clips is that of using plastics, i.e. transparent or translucent filament or fiber formed of nylon, polymethylmethacrylate or other similarly chemically pure and biologically inert materials known and available in the art. Fastening of these usually difficult to handle thin sections of plastics, however, has heretofore presented serious manufacturing problems. Staking, press fitting or interference fitting and other such attempts to fasten plastic iris clips in place are inherently difficult and tedious operations attended by high scrap yield and usually less than complete assurance against loosening or disconnection of parts during or following surgical implantation.
The use of adhesives which may avoid some of the problems of mechanical fixation procedures is, on the other hand, often frowned upon for reasons of possibility, however small, of dangerous loosening and/or disasterous detachment of parts in the eye as a result of attack upon the bond or adhesive itself by ocular fluids.
In view of the foregoing, it is a principle object of this invention to overcome present difficulties and drawbacks attending the fixing of iris clips to lenses of pseudophakoi and more particularly to overcome the problems and difficulties currently experienced in providing these lenses with iris clips formed of plastic materials.
More specifically, it is an object of the invention to provide novel and improved means and method for fixing plastic iris clips to lenses of pseudophakoi wherewith the attachment can be made simply efficiently and economically and especially with an assurance of permanence throughout the expected useful life of the product.
Other objects and advantages of the invention will become apparent from the following description.